@zinky: To troubleshoot the issue, please start by pressing the Volume Down and Side Keys together for around 10 seconds until the phone restarts, as this will refresh the device and address any temporary issues. Don't worry, this won't affect your personal data or settings. Now, head to Settings > Connections > Flight Mode, and toggle this off if applicable, followed by More connection settings > Nearby device scanning > On. You should also make sure that the A33's are up to date by heading to Settings > Software Update > Download and Install.
Following these steps, please head back to Settings > Connections > Bluetooth > On > Place the SumUp card reader in pairing mode by following the manufacturers instructions, and select it from the list of available devices to complete the connection.
